Abstract 57P
Background
Head and neck squamous cell carcinoma (HNSCC) is a cancer which arises from oropharyngeal tissues. The endothelial growth factor receptor (EGFR) over expression promotes tumour aggressiveness, while CD8+ T cells have cytotoxic activity against tumour. In the present study, we hypothesized that prognostic impact of EGFR over expression may depend on enrichment of CD8+ T cells within the tumour micro-environment (TME) in patients with HNSCC.
Methods
Gene expression data of patients with HNSCC were selected from web-based gene survival analyzer Kaplan Meier Plotter (KM plotter) to demonstrate association between EGFR expression and long-term outcomes for increased and decreased amounts of CD8+ T cells in their TME. The 5-year overall survival rate was calculated in study cohorts which stratified by optimal threshold of EGFR expression level.
Results
A total of 445 patients with HNSCC were selected from an online KM plotter database and patients with increased and decreased amounts of CD8+ T cells in their TME were 267 and 178, respectively. The EGFR over expression was significantly associated with increased risk of mortality in both patients with increased (HR=1.62, 95% CI 1.12-2.35, p=0.010) and decreased (HR=1.71, 95% CI 1.08-2.70, p=0.021) amounts of CD8+ T cells in their TME. Median survival time and overall survival rate was significantly lower in patients with decreased amounts of CD8+ T cell in their TME (38 months for low expression cohort vs. 19 months for high expression cohort, p=0.021) (Figure 1A) than patients with increased amount of CD8+ T cells in their TME (56 months for low expression cohort vs. 31 months for high expression cohort, p=0.010).
Conclusions
Patients with HNSCC who had decreased amounts of CD8+ T cells in their TME have worse outcomes compared to their counterparts who had rich CD8+ T cells in their TME regardless of EGFR over expression. Therefore, concomitant immunotherapy using immune checkpoint inhibitors additional to EGFR targeted therapy may be beneficial for this high risk population.
Legal entity responsible for the study
The authors.
Funding
Has not received any funding.
Disclosure
All authors have declared no conflicts of interest.